The present invention relates in general to signal communication and in particular to signal communication structures and methods for making the same.
An infrared (IR) transceiver is a device that transmits and receives IR light signals. A typical IR transceiver includes an IR photodiode (PD) as a receiver, an IR light emitting diode (LED) as an emitter, and an integrated circuit (IC). Normally, the IC amplifies the photo-electric current of the receiver during data reception, as well as drives the emitter to emit IR signals during data transmission.
Due to the ever-decreasing size of electronic devices, there is a high demand for small transceiver packages. One existing method for reducing the package size of a transceiver consists of reducing the size of the IC and the number of pins needed for the transceiver application.
Another existing method for reducing package size is to stack the PD on the IC, which includes physically coupling the IC and PD, using xe2x80x9cChip-on-Chipxe2x80x9d (COC) technology and wire-bonding both the PD and the IC to the transceiver substrate. However, in this single module, the size of the top surface (i.e., the light-collecting surface) of the PD that is coupled to the IC is limited by the size of the IC.
To demonstrate, the aforementioned wire bonding of the IC to the substrate occurs via wire-bondable pads situated on the periphery of the surface of the IC to which the PD is coupled. Therefore, these pads must be available (i.e., unobstructed) when the PD is coupled to the IC. Accordingly, the dimensions of the surface of the PD coupled to the IC can not be such that this surface covers or otherwise obstructs these wire-bondable pads. As a corollary, the dimensions of this surface can not be larger than the dimensions of the surface of the IC to which PD is coupled.
Furthermore, the dimensions of the light collecting surface of the PD correlate to those of the surface of the PD coupled to the IC. Therefore, since the surface of the PD coupled to the IC may not be larger than the surface of the IC to which the PD is coupled, neither may the light-collecting surface of the PD be larger than the surface of the IC to which the PD is coupled.
The present invention is directed to signal communication structures and methods for making the same. One embodiment of the present invention allows a communication surface of a signal communication element to be larger than a surface of an integrated circuit chip to which another surface of the signal communication element is physically coupled. Since, as a result of the above, the communication surface of the signal communication element may be larger than that which was previously achievable, it follows that the maximum communication distance of the element is extended. The aforementioned signal communication surface may be a signal collecting surface or a signal emitting surface.
Furthermore, one embodiment of the present invention comprises a signal communication structure having a signal communication element, an integrated circuit chip, and a substrate. The signal communication element is physically coupled to the integrated circuit chip. In addition, the signal communication element is communicatively coupled to the substrate. Examples of the signal communication element include a signal emitter and a signal receiver.
The integrated circuit chip is communicatively coupled to the substrate in a manner allowing for the size of a communication surface of the signal communication element to be larger than that of the surface of the integrated circuit chip to which another surface of the signal communication element is physically coupled. In one embodiment, the integrated circuit chip is flip-chip bonded to the substrate. Since flip-chip bonding, unlike the earlier-discussed wire bonding, does not require bond pads to be available on the surface of the integrated circuit chip to which the signal communication element is physically coupled, the size of the communication surface of the signal communication element may be larger than that of the surface of the integrated circuit chip to which the signal communication element is coupled. Since the size of the communication surface may be larger, so to may the maximum distance at which the signal communication structure may communicate with another device.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.